Inferior Vena Cava

The kidneys are the primary organs of the urinary system. The kidneys are the organs that filter the blood, remove waste, and excrete waste in the urine. They are the organs that perform the functions of the urinary system. The other components are accessory structures for removing urine from the body. The right kidney is usually slightly lower than the left because the liver pushes it down. The kidneys, protected by the lower ribs. Each kidney contains more than a million functional units, called nephrons, in the parenchyma (cortex and medulla). A nephron has two parts: a renal corpuscle and a renal tubule.